What is Magnetic monopoles: Definition and 48 Discussions

In particle physics, a magnetic monopole is a hypothetical elementary particle that is an isolated magnet with only one magnetic pole (a north pole without a south pole or vice versa). A magnetic monopole would have a net "magnetic charge". Modern interest in the concept stems from particle theories, notably the grand unified and superstring theories, which predict their existence.Magnetism in bar magnets and electromagnets is not caused by magnetic monopoles, and indeed, there is no known experimental or observational evidence that magnetic monopoles exist.
Some condensed matter systems contain effective (non-isolated) magnetic monopole quasi-particles, or contain phenomena that are mathematically analogous to magnetic monopoles.

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  1. O

    I Why could magnetic monopoles exist?

    Hi all, In textbooks and all other places they are saying that in principle magnetic monopoles can exist but yet have not been found (isolated). My pain increases further when I see a theoretical physicst say statements like, "We do not know of any theoretical reason why magnetic monopoles...
  2. P

    A Questions about magnetic monopoles

    So far as I know there are no monopoles in the electro-weak sector of standard model. So people look for it in the GUT and SUSY sectors. However, they are predicted to be heavy(order of Planck mass). There have been studies from LHC attempting to detect monopoles. So here are my questions: 1...
  3. C

    Potential created by two magnetic monopoles

    Homework Statement Determine the expression for the potential created by two magnetic monopoles (one positive, the other negative) that are equidistant from Earth's center (a/2 is the distant from each monopole to the Earth's center) and that are placed in the rotation axis. Homework Equations...
  4. jeffinbath

    Macroscopic magnetic monopoles are possible?

    School physics has always taught us that the big difference between a magnetised object and an electrostatically charged object is that the latter has on it an isolated positive or negative charge whereas the former cannot be an isolated N or S pole, ie. you cannot have a magnetic monopole on a...
  5. Yonah

    Why would a magnetic monopol's field be 1/r^2?

    Hi, I was reading Purcell's Electricity and Magnetism. It says that if there were a magnetic charge, its field would behave like an electric charge (field pointing out radially and magnitude decreasing as 1/r^2). Why? Could this be deduced from magnetic fields produced by electric charges? If...
  6. W

    B Could spin be a combination of magnetic monopoles?

    Hey all, Is it correct to say that magnetic moment of particles with spin is because of the spin itself, and has nothing to do with any moving charge? The exception here would be the photon of course, but I'm not sure whether "photon spin" is the same kind of angular momentum as the spin of...
  7. P

    Field Energy of Permanent Magnets vs. Magnetic Monopoles

    When two permanent magnets attract, their magnetic fields reinforce each other, whether they are stacked on their ends, in which case they are pointing the same direction, or whether they are stuck on their sides, in which case the two magnets are pointing in opposite directions. Everyone here...
  8. J

    Measuring Magnetic Monopoles: Unique Signatures in Magnetic and Electric Fields

    Supposed there were magnetic monopoles.. how do you measure them? Any unique signature to look in its magnetic and electric field (to what extend would these two be produced at all)?
  9. D

    Magnetic Monopoles: Existence, Electric & Magnetic Fields

    Do magnetic monopoles exist? Is magnetic field an extended version of electric field? What electric field in space is made of? Do moving charges produce magnetic field in addition to electric field or just the electric field converts to magnetic field?
  10. G

    A New methods to find magnetic monopoles?

    Everyone is familiar with magnets and their attraction to iron and several other elements. Ferromagnetic attraction has been observed for thousands of years. It has an "opposite", the Meissner effect. However, mankind could not observe such an effect before the advent of refrigeration, which...
  11. S

    Magnetic Monopoles: Investigating Spin-Ice Evidence

    (This is not really an advanced question, but one for physicists advanced in this science, which I am not.) In fairly recent investigation, the signature of Dirac monopoles was observed in spin ice. Say I possessed a consistent mathematical development allowing for both magnetic monopoles and...
  12. V

    How would *You* detect magnetic monopoles?

    As far as I'm aware of, a lot of models in particle physics and in the so called grand unified theories postulate the existence of magnetic monopoles. When I was an undergraduate student I always thought that it was fascinating that so much could be built theoretically without the CONCRETE...
  13. jerromyjon

    Magnetic Monopoles: Exploring the Mystery of Lone Protons

    Simple question. Why isn't a lone proton with no electrons considered a monopole?
  14. shounakbhatta

    Magnetic monopoles, fine structure and String theory

    Hello, Can anybody please explain me how magnetic monopoles, fine structure constant and string theory are related to each other? Thanks
  15. P

    Magnetic monopoles are beyond me

    How can you possibly have a magnetic monopole? The field lines must terminate somewhere, surely! I heard about them on a cosmology video on YouTube.
  16. L

    Magnetic monopoles and Lorentz force law

    Hi buddies Homework Statement Show that the Lorentz Force Law generalizes to F=q_e (\vec E+ \vec v \times \vec B)+ \frac {q_m}{\mu _0} (\vec B - \frac{\vec v}{c^2} \times \vec E)[/tex] when there are magnetic monopoles Homework Equations - The Attempt at a Solution Well, not much to say...
  17. C

    Artificial Magnetic Monopoles

    http://www.sciencemag.org/content/340/6136/1076.abstract Get ready to write Maxwell's equations in short form... CW
  18. tom.stoer

    Magnetic monopoles and Noether theorem

    Is there a Lagrangian from which the modified Maxwell equations including a magnetic charge density (magnetic monopoles) can be derived? Can one introduce a matter part (like in the Dirac Lagrangian) which reproduces the magnetic charge density? Does this Lagrangian have a symmetry which...
  19. D

    Are magnetic monopoles expected?

    Do physicists expect to find magnetic monopoles once a sufficiently obnoxious particle accelerator is built?
  20. A

    Why are magnetic monopoles so heavy?

    My question is in two parts. What is the origin of the electric field from an electric charge and why electron can have so small mass? While on the other hand for a magnetic monopole to create a magnetic field needs to be so heavy? And if the magnetic monopole is a hadron what are the...
  21. R

    What would have been the Maxwell's equations if there were magnetic monopoles?

    I am specifically talking about differential forms of Maxwell's equations here- I think ( Tell me if I am incorrect here...) since the divergence of the magnetic field is zero, we have to say it is incorrect for my above problem, so the equation should have been the divergence of magnetic field...
  22. J

    A method to detect fermionic magnetic monopoles?

    Monopoles have never been detected using magnetic methods. Perhaps that is because they now exist as bound states of North and South monopoles and therefore act only as magnetic dipoles rather than magnetic poles. I propose an electric method that might detect even bound monopole states...
  23. J

    Questions abot magnetic monopoles

    If magnetic monopoles exist: 1/ Would there be two types: North and South? 2/ If a monopole was a fermion would it have an intrinsic electric dipole moment (in analogy to normal charged fermions that have an intrinsic magnetic dipole moment)? 3/ Could the cosmological dark matter be...
  24. A

    Would magnetic monopoles violate the conservation of energy?

    My guess is that they don't since it's thought that they might be possible, but here's why I'm asking this question: in the magnetic field created by a magnetic dipole, couldn't you place a magnetic monopole into the field (make sure it stays on the set path) and have it circulate continuously...
  25. Q

    Are Magnetic Monopoles Related to the Relativistic Effect of Magnetism?

    Is the non-existence of magnetic monopoles a fact that can be predicted from classical electromagnetic theory or is it just an empirical fact that Maxwell simply added to his set of equations? Second question: is there any relation between this two facts: 1. There are no magnetic monopoles...
  26. A

    Translate this article on magnetic monopoles?

    I need to write about this experiment. I don't quite understand what is going on in most of it; it is written a little above my knowledge level. Can anyone semi translate what it is trying to say? Especially the areas of information around the figures. Thanks in advance...
  27. C

    Homework EquationsMagnetic Monopoles: Exploring North & South Poles

    Magnetic Monopoles?? Homework Statement why do such things exist?? how exactly do they work? when cutting a bar magnet into half, both halfs have their own north and south pole right?? found this excerpt on the internet(i'm currently learning magnetism )If you've ever seen a compass, you...
  28. L

    Electromagnetic field strength tensor- Magnetic monopoles

    Hey! I stumbled across this problem while reading Wald's "General Relativity", but it belongs to Electrodynamics. In problem 3 of chapter 6 one has to find the general form of a static, spherically symmetric Maxwell tensor, which is clearly F_{ab}=A(r)(dt)_a \wedge (dr)_b+B(r)r(d\theta)_a...
  29. N

    Unraveling the Mystery: The Quest to Understand Magnetic Monopoles

    magnetic monopoles?? why don't magnetic monopoles exist??
  30. T

    Magnetic Monopoles: Violating Conservation of Energy?

    Why some say that the existence of magnetic monopoles would violate the conservation of energy law?
  31. U

    Exploring Magnetic Monopoles: Questions from a Beginner

    Hey guys, I'm new to this forum and I have no formal degree or education in physics of any type, but I'm very interested in physics and only know what I've researched on my own. I know that magnetic monopoles are not supposed to exist, although I did read of some experiments that yielded...
  32. F

    Magnetic Monopoles: Theory or Reality?

    http://www.sciencedaily.com/releases/2009/09/090903163725.htm I found this article while reading up about magnetic monopoles. It says the they have observed monopoles, I went to my physics lecturer with this and she told me that is a false article and that monopoles are still only theoretic...
  33. A

    Magnetic Monopoles and Gravity

    Maxwell's equations in the covariant form are the most general relations expressing electromagnetic phenomena in the presence of gravity. Now \nablaB=0 does not follow in a general way as a necessary condition from the covariant form of the Maxwell's equations. We can always calculate the...
  34. P

    Scalar and vector potentials and magnetic monopoles

    Homework Statement Write down expressions oer E and B fields in terms of \varphi and \bar{A}. Demonstrate that this definition of B is consistent with the non-existence of magnetic monopoles. Homework Equations The Attempt at a Solution The first part of the question is easy...
  35. W

    Have magnetic monopoles been detected?

    http://www.physorg.com/news171209923.html Is this real? Have the researchers discovered the actual magnetic monopoles or something that because like the monopoles?
  36. W

    Magnetic Monopoles: Exploring Existence & Impact

    Can anyone explain to me why it would not be possible to write magnetic field (B) in terms of a vector potential (A) if magnetic monopoles exist please? Why aren't there any magnetic monopoles? Why can't we find them? And Why do some physicists support the idea of the existence of magnetic...
  37. W

    Magnetic monopoles, electric field lines and equipotential surfaces

    Homework Statement (i) Explain why it would not be possible to write the magnetic Field (B-field) in terms of a vector potential (A) IF magnetic monopoles existed. (ii) For an electrostatic field (E-field), define the electrostatic potential (Fi), and explain CONCISELY what is meant by a...
  38. J

    Theory about magnetic monopoles?

    I've heard some random arguments about magnetic monopoles, and don't know what I should think about them yet. I can see that such electromagnetic field could not be described by the usual potential A^\mu. Is there some modified potential that allows magnetic monopoles? Is there a lagrangian...
  39. D

    Magnetic Monopoles: Moving Charges & Existence Theory

    i read in a book that their existence can theoretically be proved. With my knowledge of moving charges-mag. field-moving charges monopoles seem a weird thing. PLEASE SUGGEST FURTHE READING OR CLARIFY IN A SIMPLE WAY
  40. petm1

    Magnetic Monopoles: Expected Characteristics & Properties

    What would be the expected characteristic properties of the two magnetic monopoles?
  41. S

    Magnetic Monopoles: Solving Energy Acquired by Dirac Charge

    this question supposes the existence of magnetic monopoles, and then redefines maxwell's eqn's as follows div(B) = dm curl(E) = -dB/dt - Jm where Jm is the magnetic current density, and dm is the magnetix charge density we are asked to find the energy acquired by a monopole with Dirac...
  42. J

    Magnetic monopoles and the quantisation of charge

    Hi all, I'm trying to follow somebody's derivation for why the existence of magnetic monopoles would demand electric charge was quantised (from http://forum.physorg.com/quantization-of-electric-charge_385.html . However I'm having problems with one of their steps. Halfway through it gets to...
  43. J

    Science behind magnetic monopoles in any depth?

    Hi, Just wondering, does anybody know of any texts or websites that go into the science behind magnetic monopoles in any depth? I'm thinking of writing a report on them as part of my A2 course but I can't find much information about them! (apart from the fact that nobody's detected them and...
  44. zeronem

    Explore Magnetic Monopoles: Existence, Force & Research

    Do Magnetic Monopoles exist? That is to say, is their a possibility that the Magnetic Flux will not be equal to zero as according to Maxwell's Electromagnetic Equations, but to equal a value which would serve to be what is called a Magnetic charge in which are the characteristics of the...
  45. T

    Detection of magnetic monopoles

    How would neutrons interact with magnetic monopoles?
  46. R

    Magnetic Monopoles: Size, Quantization, and Existence in Space

    What is the size of the smallest magnetic charge a magnetic monopole can have? And why are magnetic charges quantized inversely to electric charges? Also,can two oppositely charged magnetic monopoles exist as dipoles like for example + -.And what wavelength of radiation would such a dipole...
  47. B

    Magnetic Monopoles detected? Mayhaps

    http://physicsweb.org/article/news/7/10/2 Apparently the physicists claimed they observed the fingerprint of a monopole in momentum space?
  48. MathematicalPhysicist

    Detecting Magnetic Monopoles: Beyond Fermilab Experiments

    have magnetic monopoles been detected? and what kind of experiments are being done other than the ones being tested in the Fermi National Accelerator Laboratory in Illinois, according to this link: http://www.aip.org/physnews/graphics/html/monopole.htm for those who are unfamiliar to the...